Aluminum is an attractive candidate for use as an anode material in batteries. This metal has a high standard potential, low atomic weight, and multivalent charge. These attributes result in a theoretically high electrochemical equivalence.
In practice, however, aluminum batteries have eluded commercialization. A protective film on aluminum metal hampers its performance as an anode. The closest approach of a practical application is the aluminum/air battery. This design is a so-called “mechanically” rechargeable battery such that the aluminum anode is physically replaced after each discharge.
The best performance achieved by an aluminum/air cell is in the range of 1.2 to 1.5 v. The actual potential will depend on a number of factors, but the electrolyte, which may be a saline system or an alkaline solution, is important. A saline electrolyte has advantages for sea water batteries used in such application as ocean buoys and underwater vehicles.
Notwithstanding the limited success to date, the interest in aluminum batteries is ongoing. With this sentiment as background for further development, the goal of the present invention is to provide a truly secondary battery that can be recharged from an electrical power supply. This goal as well as other objects, features and advantages of the invention will be recognized from the following description and the accompanying figure.